224 [March, 



This genus* differs from all the three preceding ones by having 

 the head more or less angular, with smaller eyes and prominent fore- 

 head and epistome. The concave membranaceous state of the ventral 

 surface of the abdomen, which looks as if the under halves of the rings 

 had disappeared, is not exclusively confined to this genus, for the same 

 peculiarity may be observed in the Homalomyice, but the " plica " (a 

 membranous, or vascular ?, cord, with diverging processes, which con- 

 nects the base with the apex of the abdomen) is always present in the 

 latter genus, while it is very short and almost abortive in Ccelomyia. 



C. mollissima, Hal. 

 spatulata, Zett. 



This, the only known species, is peculiar by having the abdomen of the males 

 of an obovate or spatulate form ;f the wings and alulets are nigrescent ; the halteres 

 yellow ; the thorax black and unstriped ; the abdomen grey, marked with a longi- 

 tudinal line and three broad transverse marks, which assume a triangular form, being 

 attenuated towards the sides ; the legs are black, the middle femora are thickened 

 in the centre, and furnished beneath with a strong black beard ; the middle tibiae are 

 narrow at the base, and become gradually larger towards the end, which is ciliated 

 on the inner side with short hairs. 



The female has the forehead prominent, the eyes separated by a wide space of a 

 whitish-grey colour, with a black central stripe (often red in front) ; the thorax 

 grey, and rather indistinctly striped ; the abdomen short, oval, and pointed, of an 

 uniform greyish-black colour ; the wings grey, with yellow bases ; the alulets and 

 halteres yellow ; the legs simple. 



This peculiar species occurs chiefly in the north of England. I have found 

 both sexes in tolerable abundance in a swampy place in a wood near Bradford, during 

 the month of May, upon the flowers of Caltha palustris. 



(To be continued). 



ALTERNATION OF GENERATION IN THE CYNIPID2E. 

 BY J. LICHTENSTEIX.J 



So far as one genus at least is concerned, I am able to uphold the 

 theory of M. Adler. I do this with the greater pleasure, because in it 

 I recognise the laws that I have traced in my preceding works on the 

 "Homopteres monoones," and I am very glad to render deserved 

 homage to the learned compatriot of Fabricius. 



* Haliday's description is given in a note in Westwood's Generic Synopsis at the end of the 

 second volume of his Introduction to the Modern Classification of Insects, p. 143. It is as 

 follows ; "Ccelomyia. Abdomen, 6* , obovatum, ventre concavototo membranaceo (absque plica aut 

 linea coriacea longitudinali). Facies brevis impressa. Peristoma oblongum. Labium sub- 

 elongatum (membranaceum tamen). Calyptra jam minima lut in Homalomyia division 2, Delia 

 K. D.j. Antennse pedes ahuque Homalomyia." 



t I consider that this should be looked upon as a specific, and not as Haliday made it, a 

 generic character. 



X From the "Introduction" to M. Lichtenstein's Translation of Dr. Adler's treatise.— Vide 

 anU p. 215. 



